[material]: The mini chuck set is made of high quality copper material, can change the clamping capacity of the electric grinder, solve the blind zone of clamping diameter, solve the problem of incomplete clamping, high hardness, gooddurability, can guarantee long-term use. [drill sleeve size]: The brass collet package contains ten electric motorcycle drill chucks, the size is: 3.2mm, 3.0mm, 2.4mm, 2.0mm, 1.8mm, 1.5mm, 1.2mm, 1.0mm, 0.8mm, 0.5mm.(ten specifications) Please note the chuck size of your machine. [easy to use]: Brass drill pliers are easy to use, replacement accessories are quick and easy, there is no need to replace the pliers that suit your work, a wide range of applications in thedaily life, high hardness and good durability can ensure long-term use and use. [Versatile]: Brass drilling pliers are ideal for drilling ABS, plate, pressed paper, etc.with a hand drill or electric drill.The surface is smooth and burr-free. If you have any questions, please do not hesitate to contact us, we will answer you